PrBoom+ is based on the PrBoom 2.5.x line of development. It can currently be compiled in POSIX, Windows and Mac OS X environments. The current version is 2.5.1.4, released on 2016-01-10. The project saw its first developments in 2004, starting off as an unnamed PrBoom modification, but after gaining numerous additions over PrBoom it eventually adopted the separate PrBoom+ title in 2005.